Connector for coaxial cable

ABSTRACT

This disclosure describes a connector for a communications coaxial cable. The connector structure includes a collapsible bushing which is wedged into a positive grip with the cable jacket, and a separate wedge-type bushing to grip the outer conductor. A resilient seal is afforded around the center conductor. Placement of the cable in the connector and of the latter onto equipment housing requires no special tools.

United States Patent CONNECTOR FOR COAXIAL CABLE 4 Claims, 7 DrawingFigs.

U.S. Cl 339/94, 339/ 1 77 Int. Cl H0lr 17/04, H01 r 3 3 /34 Field ofSearch 339/94 A,C,M, 94, 103, 104, 177 E, 273 R,F

Elke [5 6] References Cited UNITED STATES PATENTS 2,700,140 1/] 955Phillips 2,936,440 5/1960 Mack et al. 3,107,135 10/1963 Keil 3,184,7065/1965 Atkins 3,209,287 9/ 1965 Oxner et al.

Primary Examiner-Stephen J. Novosad Assistant Examiner-Lawrence J. StaabAttorneys-R. J. Guenther and Edwin B. Cave ABSTRACT: This disclosuredescribes a connector'for a communications coaxial cable. The connectorstructure includes a collapsible bushing which is wedged into a positivegripwith the cable jacket, and a separate wedge-type bushing t6 grip theouter conductor. A resilient seal is afforded around the centerconductor. Placement of the cable in the connector and of the latteronto equipment housing requires no special tools.

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ATTORNEY CONNECTOR FOR COAXIAL CABLE FIELD OF THE INVENTION Thisinvention relates to coaxial cable terminations and more particularly toa coaxial cable connector suitable for use in high frequency coaxialsystems using corrugated outer conductors.

BACKGROUND OF THE INVENTION The impending growth of communicationscoaxial cable systems having operating bandwidths in excess of 200MHz.has imposed requirements on the associated coaxial connectors that arenot suitable met by existing connectors.

One principal defect of earlier coaxial cable connectors in volvesseparation of the outer jacket from the connector, which subjects theouter conductor to corrosion and eventual malfunction. Additionally,because of irregularity in the outer jacket diameters, reliable airseals around the outer jacket have been difficult to achieve with theusual expedients of crimp-type or O-ring seals.

Further, in pressurized coaxial systems it is necessary to prevent airleaks around the center conductor. Earlier type connectors have beennotably deficient in this respect.

It further is necessary to assure a mechanically strong link between theouter conductor and the connector to provide electric continuity andhigh structural reliability.

Numerous expedients can be enlisted in the separate solutions to theforegoing concerns, but the net result still is not practicable unlessit is both inexpensive and simple to install in large numbers. Also tobe met are the electrical requirements of approximately 75ohms impedanceand overall compatibility with the new 0.375-inch diameter corrugatedcoaxial cable shortly to be adopted by the carriers.

Accordingly, one object of the invention is to assure greaterreliability in the connection and splicing of corrugated coaxial cables.

A more specific object of the invention is to grip the polyethylenejacket of such cables with sufficient positive force to avoid jacketpullout.

A further object of the invention is to provide a reliable air sealaround the center conductor.

Yet a further object of the invention is to achieve an airtight sealaround the outer jacket regardless of the nonuniformity thereof.

An important object of the invention is to directly grip the outerconductor to the connector.

SUMMARY OF THE INVENTION In broadest terms the invention ischaracterized by the use in a coaxial cable connector of separatecompression-type bushings to engage the outer jacket and the outerconductor respectively, and a compliant washer assembly to effect a sealaround a central conductor.

In a specific embodiment, compression of the slotted bushing onto theouter plastic jacket is realized by engaging the bushing in the taperedinterior of a fastening glandv As the bushing moves forward in responseto tightening, it also causes sealing compound to be extruded into asealing darn around the jacket, to thus achieve a positive air sealbetween the jacket and the connector.

The invention, its further objects, features, and advantages are morefully partieularized in the below description of an illustrativeembodiment.

DESCRIPTION OF THE DRAWING FIG. 1 is an exploded side perspectivediagram of the connector;

FIG. 2 is a side perspective view of a mounting detail for the outerconductor;

FIG. 3 is a side perspective view showing the inner conductor seal;

FIG. 4 is a side perspective assemble of the entire connector;

FIG. 5 is a side perspective diagram in partial breakaway showingthejacket gripping means;

FIG. 6 is a sectional side view of the center conductor sealing means;and

FIG. 7 is a sectional side view of the outer jacket sealing means.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT FIG. 1 shows anexploded view of the inventive coaxial connector shown fully assembledin FIG. 4. The connector consists of the main body 1, a connector drivebody 2, an anchor fitting 3, disposed on one side of drive body 2, awedge bushing 4 abutting the other side of body 2, a slotted bushing 5fitting in the far end of main body 1, and an internally tapered hex-nut6.

Pursuant to one aspect of the invention, a washer 7 advantageously ofbrutal rubber and including a central orifice 8 is sandwiched betweentwo dielectric discs 9, 10 which have much larger central orifices II.The interior of drive body 2 includes a circumferential abutment I12,and the assembly of discs 9, l0, and washer '7 are seated into thefitting 3 to lodge against the abutment 12.

The central orifice of washer 7 is normally 0.070 inch in diameter,while the coaxial cable center conductor 20 shown in FIG. 3, forexample, is 0. I00 inch in diameter. Insertion of center conductor 20through the disc and washer assembly, as seen in FIG. 6, produces asubstantial outflexing of rubber washer 7, thus to achieve a verysubstantial airtight seal around conductor 20. A seal between theinterior of the flange l3 and the outer diameter of the washer 7 also isafforded by the action of discs 9, 10. The edge of flange l3advantageously is swaged circumferentially to lock the assembly of discs9, l0 and washer 7 against abutment 12.

Anchor fitting 3 engages to equipment housing (not shown), through itsthreaded sleeve 14. The interior of fitting 3 rides on the flange 13 ina slight clearance fit. The interior face of anchor fitting 3 consistsof a hexagonal nut 15 with a seat 16 to receive an O-ring seal 17depicted in FIG. 1 as being at the far end of flange 13. Interior of theseal 17 is a locknut l8 engaged to a threaded portion 19 of the flange13.

With anchor fitting 3 disposed on flange 13 in compressing relation withseal 17, a metal ring 2E is engaged in the end groove 22 of flange 13.As depicted in FIG. 3, ring 21 protrudes beyond flange l3 and serves asa lock to engage the shoulder 23 of anchor fitting 3 so that the latteris secured to flange I3. Thereafter, locknut I8 is tightened towardfitting 3 to further compress O-ring seal I7 and thus provide anairtight seal between the interior of anchor fitting 3 whichcommunicates with equipment housing (not shown) and the outsideenvironment to which flange I3 is partially exposed.

The positive engagement of corrugated outer conductor 30 to theconnector will now be described. Wedge bushing 4, de picted in FIG. I,has a flared section 24 with its end 25 diameter substantially equal tothe outer diameter flange 26 of connector drive body 2. A section ofplastic outer jacket 40 is removed as seen in FIG. 2, exposing the outerconductor 30. The latter in turn is cut back, exposing a section ofinner conductor which as earlier described engages the washer 7. Priorto engagement, the wedge bushing 4 is inserted under the outer conductor30 which by way of preparation is slit in three places approximately I20apart. The main body I, the slotted bushing 5, and tapered nut 6 areplaced in position (not shown) on the coaxial cable in the sequence andorientation depicted in FIG. I.

Main body 1 includes an O-n'ng 27' in an interior end seat 28, and athreaded interior portion 29 adjacent thereto. Threads 29 engage theexterior threads 31 of the flange 26. Further turning of drive body 2brings the O-ring 27 into sealing engagement with flange 32 of connectordrive body 2. In this process, the flared section 24 of wedge bushing 4upon which .the outer conductor 30 is lodged, is contacted by theinternal tapered section 33 of main body I. It is thus seen that withthe tightening ofdrive body 2 into connector main body I, extremecompressive force is applied to the outer conductor 30 engaged betweenflared section 24 and the internal tapered section 33 of main body 1.This expedient provides very substantial electrical and mechanicalengagement between the outer conductor 30 and the coaxial cableconnectOl'.

The seal afforded between O-ring 27 and flange 32 is a pressure seal aswell as a moisture seal to make possible the application of gas pressurethrough suitable entrances (not shown) in one of the hexagonal sides ofmain body 1.

Pursuant to a further aspect of the invention and as depicted in FIGS.1, 5, and 7, a positive gripping of the outer jacket 40 is afforded byslotted bushing in the following fashion. Bushing 5 has in its interiortwo annular teeth 34, 35. Bushing 5 also includes a number of slots 36in its exterior end which is also slightly tapered inwardly. The end 37of bushing S is provided with plural longitudinal ridges 38.

A sleeve 47 extends from the tapered nut 6 to form an electrical contactsurface to the lightening and noise shield of multisheathe cables (notshown).

As seen in FIG. 5, the nut 6 interior includes a threaded end 39 andoutward thereof a tapered portion 41. The slotted bushing 5 is initiallyloosely engaged to the outer jacket 40. When the bushing 5 is suitablylocated on the jacket 40, the nut 6 is moved over the bushing 5 and intoengagement with the threaded end 42 of main body flange 43. It isreadily seen that with tightening of the nut 6, the annular teeth 34, 35of the slotted portion of bushing 5 are compressed and collapse onto andinto the jacket 40, engaging it in the manner of a fishhook.

Destruction tests have indicated that the gripping force applied to theouter conductor 30 and to the outer jacket 40 by the expedients abovedescribed are so great that the pullout force required to dislodge thecable from the connector is 75 percent of the breaking strength of thecable itself.

The slotted bushing 5 fulfills the further inventive function ofefi'ecting' a gas and watertight seal between the outerjacket 40 and theenvironment to which the connector is exposed, the manner of which isdepicted in FIG. 7.

As shown therein, the bushing end 37 with its ridges 38, protrudes in aslight clearance fit into the interior of flange 43 of main body l,which interior is designated 44. Prior to takeup of the nut 6, a stripof sealing compound 45 is placed into the interior section 44 where itlodges against the interior shoulder 46 ,of flange 43. Then, as nut 6 istaken up and the slotted bushing is engaged on the tapered interior 41thereof, the edge of the slotted bushing 37 is forced end-first into thesealing compound 45, the latter in turn is caused to form a collar andbe extruded along the interface between bushing 5, outer jacket 40, andinterior 44 of the main body flange 43,

The above-described coaxial cable connector is seen to provide apositive gas and watertight seal to the inner conductor, a positive highstrength electrical and mechanical joint between the outer conductor andthe connector. a sturdy gripping of the outerjacket by the connector andan extruded seal between the outer jacket and the environment of theconnector.

Various modifications will be obvious to those skilled in the art upon astudy of the foregoing disclosure; and it is to be understood that thespirit and the scope of the invention are embraced in the claims tofollow.

We claim:

1. For a coaxial communications cable consisting of a center conductor,a corrugated outer conductor and a plastic jacket surrounding said outerconductor, a connector comprising:

a chambered main body comprising a central internal tapered section andan inner sealing dam adjacent thereto containing a sealing compound;

a first bushing having a cylindrical section fitting under the surfaceof said outer conductor at a selected point and a conic section adjacentthereto;

a second bushing comprising a tapered body with plural interior annularteeth for gripping said jacket, and a cylindrical end comprisingexterior longitudinal slots;

first means for driving said first bushing conic section into wcdgingengagement with said main body tapered section to grip said outerconductor therebetween; and

second means for compressing said second bushing teeth into grippingengagement with said jacket, said second means also driving saidcylindrical end into said sealing dam to hydraulically disperse saidsealing compound along the interfaces of said second bushing, saidjacket and said second means.

2. A connector pursuant to claim 1, wherein said first means is a drivebody comprising a first flanged end for threadably engaging said mainbody chamber and affecting said wedging engagement with its end face.

3. A connector pursuant to claim 2 wherein said drive body furthercomprises a second flanged end with an annular interior seat, a pair ofplastic washers sealably engaged in said seat, and a compliant washersupported between said discs, the compliant washer having a centralorifice less than the diameter of said central conductor for affecting aseal around the latter.

4. A connector pursuant to claim 3, wherein said drive body secondflanged end further comprises a threaded interior section with a lockingnut thereon and a depressed end groove for receiving a snap-mountablemetal ring, and said connector further comprises a threaded anchorfitting slidably engaged on said flange between said ring and saidlocking nut, said fitting being held therebetween by action of saidlocking nut.

1. For a coaxial communications cable consisting of a center conductor,a corrugated outer conductor and a plastic jacket surrounding said outerconductor, a connector comprising: a chambered main body comprising acentral internal tapered section and an inner sealing dam adjacentthereto containing a sealing compound; a first bushing having acylindrical section fitting under the surface of said outer conductor ata selected point and a conic section adjacent thereto; a second bushingcomprising a tapered body with plural interior annular teeth forgripping said jacket, and a cylindrical end comprising exteriorlongitudinal slots; first means for driving said first bushing conicsection into wedging engagement with said main body tapered section togrip said outer conductor therebetween; and second means for compressingsaid second bushing teeth into gripping engagement with said jacket,said second means also driving said cylindrical end into said sealingdam to hydraulically disperse said sealing compound along the interfacesof said second bushing, said jacket and said second means.
 2. Aconnector pursuant to claim 1, wherein said first means is a drive bodycomprising a first flanged end for threadably engaging said main bodychamber and affecting said wedging engagement with its end face.
 3. Aconnector pursuant to claim 2 wherein said drive body further comprisesa second flanged end with an annular interior seat, a pair of plasticwashers sealably engaged in said seat, and a compliant washer supportedbetween said discs, the compliant washer having a central orifice lessthan the diameter of said central conductor for affecting a seal aroundthe latter.
 4. A connector pursuant to claim 3, wherein said drive bodysecond flanged end further comprises a threaded interior section with alocking nut thereon and a depressed end groove for receiving asnap-mountable metal ring, and said connector further comprises athreaded anchor fitting slidably engaged on said flange between saidring and said locking nut, said fitting being held therebetween byaction of said locking nut.